The overall objectives of the proposed research are to determine the role of the viral genome in the production, expression and maintenance of tumor specific transplantation antigen (TSTA) in cells transformed or infected with papovavirus SV40 and to investigate the relationship among TSTA and other surface changes. The induction of TSTA will be measured using in vitro techniques which specifically detect cellular immune reactivity. The role of the viral genome in the induction of TSTA will be investigated by using inhibitors and by isolating temperature-sensitive mutants of SV40 which are defective in the synthesis of TSTA at the non-permissive temperature. This approach will allow us to determine which genes of SV40 are necessary for the production and maintenance of TSTA and whether the protein is coded for by the viral genome, as well as the role of TSTA in tumor rejection. BIBLIOGRAPHIC REFERENCES: Tevethia, S.S., Zarling, J.M. and Flax, M.H. 1976. Macrophages and the destruction of syngeneic virus induced tumors. In "Immunobiology of the Macrophage," (D.S. Nelson, ed.) pp. 509-533, Academic Press, New York. Tevethia, S.S., Waneck, G. and Tevethia, M.J. 1977. Immune response of athymic-nude mice to papovavirus SV40 tumor associated antigens. Int. J. Cancer. in press.